As a matter of fact, for each substitution of the independent variable,
there are 8 substitutions of the dependent variable on account of the homotopic transformations.
These are given by the transformations \(M_{1}-M_{4}\) 
and \({M}_{25}-M_{28}\)  of Maier's table but here, as in [1]} and [2]},
they are denoted by
\(T_{i}\)  (\(i=1,\cdots ,8\) ) according to
\(&&T_1=M_1,\quad T_2 =M_{25}, \quad T_3=M_{2},\quad T_4=M_{26},\nonumber \vspace{5.69054pt}\\&&T_5=M_3,\quad T_6=M_{27},\quad T_7=M_4,\quad T_8 =M_{28}.\) 
